Public transportation has been provided in Los Alamos County by various organizations since 1980. Transit services first operated under the name Los Alamos Transit Operations, a small private corporation with only two buses running once per day between White Rock and Los Alamos National Laboratory (LANL). Los Alamos Transit Operations dissolved in 1982.

Over the next 25 years, transit service was provided by Los Alamos Bus System, Inc. (LA Bus), a small non-profit organization. LA Bus operated a fleet of 15 buses and primarily served LANL, with very little community-wide service. Depending on the source, it is estimated that LA Bus carried anywhere from 30,000 to 70,000 passengers a year.

On March 28, 2007, at the request of the community and LA Bus, an agreement was reached for Los Alamos County to assume all public transportation operations. Atomic City Transit was born and service commenced on October 1, 2007.

Atomic City Transit today...

Today, Atomic City Transit operates four distinct modes of service, namely, 1) fixed route transit service in Los Alamos and White Rock; 2) evening demand response (Dial-a-Ride) service for the general public; 3) ADA complementary paratransit (ACT Assist) service with an origin and destination anywhere within Los Alamos County; and 4) shuttle service between White Rock Visitor Center and Bandelier National Monument during the peak visitor season.

Atomic City Transit also provides special event services, including shuttle service for the County's annual Fourth of July fireworks show, and safe-ride-home service on select holidays.

When Atomic City Transit began operating in 2007, it was estimated that annual ridership would reach 100,000 one-way passenger trips. However, ridership far exceeded all expectations, with a total of 254,502 passenger trips during the first year. In the past four years (2012-2015), an average of over 545,000 annual passenger trips have been provided, with a peak of 562,226 trips in 2012.